Valvular control circuit

ABSTRACT

Valvular control circuit (10) comprising a first valve element (12) coupled with a manual drive member (20) to generate a pilot light (21), a second valve element (14) coupled with a second valve switch (15), a control and command unit (16) coupled with a DC/DC electric voltage converter (17) and able to command said second valve switch (15) by means of a command signal, wherein said valvular control circuit (10) comprises a first thermoelectric power source (22) coupled with the DC/DC electric voltage converter (17), and a second thermoelectric power source (23) coupled with at least one of either the first valve element (12) or the second valve element (14), said thermoelectric power sources (22, 23) both being fed by a pilot light (21).

FIELD OF THE INVENTION

The present invention concerns a valvular control circuit associablewith an apparatus powered by gas, such as for example natural gas,methane, propane or other gases, or mixtures of air and gas.

By way of non-restrictive example, the apparatuses in question compriseboilers, storage water-heaters, stoves, furnaces, fireplaces or othersimilar or comparable apparatuses.

BACKGROUND OF THE INVENTION

Valvular control circuits are known, able to control and regulategas-powered apparatuses in which there are one or more safety and/orregulation valves that, depending on the regulation set on each occasionby the user, power the main burner of the apparatus.

Some valvular control circuits have a thermoelectric power source that,cooperating with an auxiliary heat source, generally called pilot light,makes the valvular control circuits self-powered.

During start-up, the pilot light is generated by a manual drive that ismaintained functioning by the user until the thermoelectric power sourcegenerates a stable electric power voltage sufficient to power both thecontrol electronics and also the safety and/or regulation valves.

The thermoelectric power source typically generates a limited electricvoltage that has to be amplified in order to power the controlelectronics and at the same time to supply the necessary power to drivethe safety and/or regulation valves.

In this context, due to the slow time constant of the thermoelectricpower source and the drops in voltage at the heads of the safety and/orregulation valves, during start-up the user has to keep the manual driveactivated for rather a long time.

If the apparatus is a storage water-heater, it is fundamental toguarantee a continuous functioning and, in this context, the elementmost at risk is the thermoelectric power source.

Indeed, since it is heated to temperatures in the range of 600° C.-750°C., the thermoelectric power source is very sensitive to oxidation,which leads to progressive wear and eventually breakage.

The variability of the pilot light caused for example by drafts,composition and pressure of the power gases, drops of condensation etc.,makes it difficult to assess the state of wear of the thermoelectricpower source.

This assessment is made even more complicated since, as thethermoelectric power source approaches breakage point, it is subjectedto a deterioration that is not distinguishable from the variations dueto its normal functioning.

Furthermore, from a safety point of view, it is necessary that thevalvular control circuits cannot be tampered with by a user, or if thishappens, the tampering must be detected so that the apparatus can bepromptly blocked, so as to prevent accidents that can even be veryserious.

There is therefore a need to perfect and make available a valvularcontrol circuit that overcomes at least one of the disadvantages of thestate of the art.

The purpose of the present invention is to provide a valvular controlcircuit associated with a gas-powered apparatus that allows to powerquickly both the control electronics and also the safety and/orregulation valves at every start-up, or following temporarymalfunctions.

Another purpose is to provide a valvular control circuit that alsoallows to program the maintenance operations and/or replacements ofparts of the valvular control circuit and/or the apparatus associatedtherewith.

Another purpose of the present invention is to provide a valvularcontrol circuit able to monitor the power condition thereof, and that atthe same time allows to promptly verify whether any dangerous tamperinghas occurred.

The Applicant has devised, tested and embodied the present invention toovercome the shortcomings of the state of the art and to obtain theseand other purposes and advantages.

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the independentclaim, while the dependent claims describe other characteristics of theinvention or variants to the main inventive idea.

In accordance with the above purposes, embodiments of the presentinvention concern a valvular control circuit comprising a first valveelement coupled with a first valve switch, a second valve elementcoupled with a second valve switch, a control and command unit coupledwith a DC/DC electric voltage converter and able to command the firstvalve switch and the second valve switch by means of a command signal,said first valve element being coupled to a manual drive member togenerate a pilot light.

According to possible embodiments, the present invention concerns avalvular control circuit comprising a first valve element coupled with amanual drive member to generate a pilot light, a second valve elementcoupled with a second valve switch, and a control and command unitcoupled with a DC/DC electric voltage converter and able to command thesecond valve switch by means of a command signal.

In accordance with one aspect of the present invention, the valvularcontrol circuit comprises a first thermoelectric power source coupledwith the DC/DC electric voltage converter, and a second thermoelectricpower source coupled with at least one of either the first valve elementor the second valve element, the thermoelectric power sources both beingfed by the pilot light.

According to possible embodiments, the first thermoelectric power sourceis coupled with the DC/DC electric voltage converter and the secondvalve element, and the second thermoelectric power source is coupledwith the first valve element.

According to possible embodiments, the second thermoelectric powersource is coupled with the first valve element and with the second valveelement.

According to a variant, the second thermoelectric power source comprisesa thermocouple.

According to a variant, the pilot light affects both the thermoelectricpower sources to an equal extent, said thermoelectric power sourcesbeing disposed at a substantially equal distance from the pilot light.

According to a possible variant, the first and the second thermoelectricpower sources are disposed in a single protective container so as to besubjected to the same heating conditions.

According to a possible variant, the valvular control circuit comprisesa rechargeable energy source removably coupled with the DC/DC electricvoltage converter and with the control and command unit.

According to a variant, at least one of either the first or secondthermoelectric power sources comprises a thermopile.

According to a variant, the first and second thermoelectric powersources are identical to each other.

According to a variant, the first and second thermoelectric powersources have, with respect to each other, one or more differentcharacteristics chosen from the time constant, electric resistance andelectromotive force which can be generated.

According to a possible variant, the control and command unit has atleast a monitoring device able to monitor the electromotive forcegenerated by one or both of the thermoelectric power sources and tosignal their functioning state and/or wear in relation to theelectromotive forces measured.

The control and command unit has, or is connected to, a sensor able todetect the electric voltage of one or both of the thermoelectric powersources and, if the electric power voltage detected is greater than athreshold value of electric voltage, or the difference of electricvoltage between the thermoelectric power sources is comprised in apredetermined voltage range, said sensor is configured to send an alarmsignal.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other characteristics of the present invention will becomeapparent from the following description of some embodiments, given as anon-restrictive example with reference to the attached drawings wherein:

FIGS. 1-5 schematically show possible embodiments of a valvular controlcircuit described in the present disclosure.

To facilitate comprehension, the same reference numbers have been used,where possible, to identify identical common elements in the drawings.It is understood that elements and characteristics of one embodiment canconveniently be incorporated into other embodiments without furtherclarifications.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

Embodiments described here with reference to the drawings concern avalvular control circuit 10 configured to control the functioning of agas-powered user apparatus.

The gas-powered user apparatuses in question comprise boilers, storagewater-heaters, stoves, furnaces, fireplaces or other similar orcomparable apparatuses in which there is a main burner 11 powered bynatural gas, methane, propane or other gases, or mixtures of air/gas.

For example, if the gas-powered apparatus is a storage water-heater, themain burner 11 is configured to heat the load 31, that is, the water, toa desired temperature.

According to possible embodiments, the valvular control circuit 10comprises a first valve 12 and a second valve 14 coupled with a secondvalve switch 15.

According to possible embodiments, the first valve 12 can be coupledwith a first valve switch 13.

It is understood that the word “valve” here means any valve element,driven mechanically, electromechanically or electrically, comprising oneor more valves associated with each other to form a functionalcomponent.

The first valve 12 and the second valve 14 can each comprise, forexample, an electrovalve that switches its state from closed to open andvice versa, when an electric command signal is sent respectively to thefirst valve switch 13 or the second valve switch 15.

During the start-up step, the first valve 12 is opened manually and thisoperation can be performed by driving a manual drive member 20.

During the switching off step, the first valve 12 can be closedelectronically, if it is associated with the first valve switch 13, ormanually in the absence of the first valve switch 13.

The first valve 12 functions as an entrance safety valve which, when itis open, allows the gas to transit from the gas feed source to the userapparatus.

The second valve 14 functions as a valve to regulate the feed gas to themain burner 11.

The second valve 14 can function as a supplementary safety valve. Whenthe second valve 14 is closed, the first valve 12 can feed only thepilot light 21 through the pilot path.

The first valve 12 and/or the second valve 14 can each be coupled with apressure regulator to define on each occasion the delivery pressure ofthe gas exiting from the corresponding valve.

The valvular control circuit 10 comprises a command and control unit 16coupled with a DC/DC electric voltage converter 17.

The command and control unit 16 is able to command the first valveswitch 13 and/or the second valve switch 15 by means of a command signalsent to them.

According to possible embodiments, the DC/DC electric voltage converter17 coupled with the command and control unit 16 is able to convert anentering DC electric voltage into an amplified DC electric voltage atexit, so as to power the command and control unit 16 with the necessaryvoltage.

According to possible embodiments, when necessary, the command andcontrol unit 16 sends a command signal to the first valve switch 13and/or the second valve switch 15 to switch the state of thecorresponding valve 12 and/or 14.

The command and control unit 16 can comprise a programmablemicroprocessor, an electronic circuit, an electronic board or othersimilar or comparable electronic unit.

The command and control unit 16 can comprise, or be connected to, aselection unit 18 configured to select the temperature to which the load31 is to be taken, for example water if the user apparatus is a storagewater-heater.

For example, the selection unit 18 can comprise a thermostat providedwith knobs and/or a user interface by means of which the user can selectthe temperature.

The command and control unit 16 can comprise, or be connected to, one ormore temperature probes 19 located in the area where the temperature isto be regulated. For example, the temperature probe 19 can be immersedinside the liquid to be heated.

The cooperation between the selection unit 18 and the temperature probe19 allows to continuously monitor and regulate the temperature of theload 31 according to the desired temperature.

According to possible embodiments, the first valve 12 is coupled with amanual drive member 20 to generate a pilot light 21.

In particular, at least during the first ignition or restarting step,the manual drive member 20 is configured to open the first valve 12 toallow the gas to transit along the pilot path and feed the pilot light21.

This can be carried out with the aid of a piezoelectric device, or othersimilar device.

The start-up or restart step is obtained while keeping the second valve14 closed, so as not to feed the main burner 11 during the start-upstep.

The manual drive member 20 can be included in the selection unit 18, orcan be connected to it, or can be independent from it.

If the manual drive member 20 is separate from the selection unit 18,the preselection of the temperature remains unchanged when the valvularcontrol circuit 10 is switched on, off or on stand-by.

According to one aspect of the present invention, the valvular controlcircuit 10 comprises a first thermoelectric power source 22 coupled withthe DC/DC electric voltage converter 17, and a second thermoelectricpower source 23 coupled with at least one of either the first valveelement 12 or the second valve element 14, said thermoelectric powersources 22, 23 both being fed by the pilot light 21.

According to possible embodiments, the first thermoelectric power source22 is coupled with the DC/DC electric voltage converter 17 and thesecond valve 14, and the second thermoelectric power source 23 iscoupled with the first valve 12.

According to a variant, the second thermoelectric power source 23comprises a thermocouple 26.

The thermocouple 26 has very quick reaction times that can furtherreduce the time for which a user has to keep the manual drive member 20in action.

This high reactivity of the thermocouple 26 also allows to detectpromptly any possible variations in the pilot light 21, and hence tointervene immediately.

One of the advantages that can be obtained according to the presentinvention concerns the possibility of effectively assessing the state ofwear of each of the thermoelectric power sources 22 and 23.

By constantly monitoring both the thermoelectric power sources 22 and23, it is possible to assess the evolution over time of the parametersthat characterize them.

In particular, from one or more differences in the temporal evolution,for example of the electric resistances, the electric voltages at theirheads, or the electric voltage on a load located between the twothermoelectric power sources 22 and 23, it is possible to determine thefunctioning state and/or the state of wear of one or both thethermoelectric power sources 22 and 23.

This combined monitoring of both thermoelectric power sources 22 and 23allows to foresee, in time, when and which source will need to bereplaced.

In fact, it is possible to define on each occasion, also withself-learning algorithms, a series of reference events in the evolutionof the parameters monitored, with which specific states of thethermoelectric power sources 22 and 23 are associated.

This not only allows to program the maintenance operations but also tomonitor in detail the functioning of the valvular control circuit 10 andof the user apparatus associated with it.

According to a variant, the pilot light 21 affects equally both thethermoelectric power sources 22 and 23, since said thermoelectric powersources 22 and 23 are disposed at a substantially equal distance fromthe pilot light 21.

According to a possible variant, the thermoelectric power sources 22 and23 are disposed in a single protective container 24, so as to besubjected to the same heating conditions.

The protective container 24 also allows to protect the twothermoelectric power sources 22 and 23 against external agents that canchange their functioning.

According to a variant, the thermoelectric power sources 22 and 23 areidentical.

The combination of one or more of the aspects described above obtainsmore advantageous solutions, since the working conditions of the twothermoelectric power sources 22 and 23 are always closer to each other.

According to a variant, the thermoelectric power sources 22 and 23 canhave one or more reciprocally different characteristic parameters,chosen from a group comprising time constant, electric resistance andelectromotive force that can be generated.

According to a possible variant, the command and control unit 16 has oris connected to at least a monitoring device 25 able to monitor theelectromotive force generated by one or both the thermoelectric powersources 22, 23 and to signal to a user their state in relation to theelectromotive forces measured by the monitoring device 25, for exampleby means of a user interface or signaling LEDs or other signaling mean.

The monitoring device 25 can be integrated in the command and controlunit 16, or can be connected to it.

The measurement of the electromotive forces generated can be carried outby measuring devices connected to the heads of the thermoelectric powersources 22 and 23.

Using two thermoelectric power sources 22 and 23 allows to obtainreliable information in rapid time, since the differential analysis ofthe trend of the electromotive forces is more precise than an analysisof the absolute values referred to a single thermoelectric power source.

In fact, monitoring only the absolute values referred to a singlethermoelectric power source, the latter would be confused with thecharacteristic fluctuations of the system.

For example, when the second valve 14 is opened, the ignition of themain burner 11 causes a corresponding temporary variation in the trendof the electromotive force generated by the two thermoelectric powersources 22 and 23.

By suitably monitoring and combining the characteristics of the twothermoelectric power sources 22 and 23, the command and control unit 16,and in particular the monitoring device 25, is able to quickly determinewhether the pilot light 21 and/or the main burner 11 have been ignitedsuccessfully.

Another advantage of having two separate and distinct thermoelectricpower sources 22 and 23 is that this also makes the feed to the commandand control unit 16 separate from the feed of one or both the valves 12and 14.

This considerably reduces the start-up times compared with feeding froma single thermoelectric power source, since the load fed is dividedbetween the two thermoelectric power sources 22 and 23.

This has the advantage that it does not require the user to prolong theaction on the manual drive member 20.

In fact, especially during the start-up step, if there is only onethermoelectric power source, it is subjected to a very high load becausethe command and control unit 16 is also present, which is alsodesignated to control the functioning of the valvular control circuit10.

Considering that the power voltage can diminish suddenly to very lowvalues, for example due to drops of condensation falling onto thethermoelectric power sources 22 and 23 and/or onto the pilot light 21,the operating continuity of the valvular control circuit 10 must beguaranteed.

With reference to FIG. 2, when the first valve 12 is driven purelymechanically, that is, by the manual drive member 20, even if thecommand and control unit 16 normally stops functioning long before thethreshold of mechanical release of the first valve 12, the latter is notaffected by the drop in voltage of the command and control unit 16.

In the event of a drop in voltage, with reference to FIGS. 1, 3 and 5,the command and control unit 16 switches both valve switches 13 and 15.

In these embodiments, when the first valve switch 13 intervenes, thefirst valve 12 is closed and consequently also the pilot path that feedsthe pilot light 21.

This causes the valvular control circuit 10 to switch off and requiresmanual rearming in order to start functioning again.

With reference to FIG. 2, this shows a solution in which the secondthermoelectric power source 23 consists of a thermocouple 26 that powersthe first valve 12, while the first thermoelectric power source 22consists of a thermopile 27 that powers both the second valve 14 andalso the command and control unit 16. Furthermore, the first valve 12 iscontrolled by a manual drive member 20.

This solution solves the problem caused by the drops in voltage becausethe first valve 12 is not switched in response to the interruption inthe power of the command and control unit 16, and stays open even forvery low power voltages, at which the command and control unit 16 wouldnot be able to function.

In other words, following a sudden drop in the power voltage, thecommand and control unit 16 and also possibly the main burner 11 canswitch off, while the pilot light 21 stays ignited, since the firstvalve 12 does not change its state.

This has the advantage that, if the command and control unit 16 stopsfunctioning, even temporarily, the valvular control circuit 10self-restores thanks to the action of the pilot light 21, which is notaffected by the interruption in the power.

In this solution too, a monitoring device 25 can be provided, able tocompare the feed of the thermocouple 26 and the thermopile 27 toestablish their degree of wear.

In this way, all the safety functions are mechanical, while the commandand control unit 16 is designated to perform a thermostat function, andto control and possibly signal the state of the two thermoelectric powersources 22 and 23.

According to a variant, at least one of the thermoelectric power sources22 and 23 comprises a thermopile 27.

According to a possible variant, the valvular control circuit 10 cancomprise a rechargeable energy source 28 removably coupled with theDC/DC electric voltage converter 17 and the command and control unit 16.

The rechargeable energy source 28 allows to activate the command andcontrol unit 16 in advance, before the time needed to activate the firstthermoelectric power source 22.

This allows the command and control unit 16 to signal quickly to theuser that the pilot light 21 has been ignited.

In fact, without this strategy, the user has to keep the manual drivemember 20 active for a time longer than that generally necessary,because the user cannot know if the pilot light 21 is actually ignitedand stable.

The fact that the pilot light 21 has been ignited can be signaled bymeans of signaling LEDs or other signaling means comprised in orconnected to the command and control unit 16.

For example, the rechargeable energy source 28 can comprise arechargeable battery, which can be connected, when necessary, to powerthe command and control unit 16.

The connection can be made automatically during the ignition of thepilot light 21, or it can be selective and set on each occasion by auser.

For example, the connection can be obtained by driving the manual drivemember 20, which in turn acts on a switch 32 put in series with therechargeable energy source 28.

It is quite clear that the valvular control circuit 10 can also functionwithout the rechargeable energy source 28, since the latter can bedisconnected or removed and the power supplied directly by the firstthermoelectric power source 22.

If one of the thermoelectric power sources 22 and 23 is a thermopile 27,it is possible to use the excess energy possibly available at its headsto recharge the rechargeable energy source 28.

According to possible embodiments, the command and control unit 16 canhave, or be connected to, a sensor 29 able to detect the electricvoltage of one or both of the thermoelectric power sources 22 and 23and, if it is greater than a threshold value of electric voltage, thesensor 29 is configured to send an alarm signal 30.

The presence of the sensor 29 increases the overall safety level of thevalvular control circuit 10 and of the user apparatus connected to it,since it allows to detect promptly whether a user connects an externalpower source, such as for example a battery, to the valves 12 and 14and/or to the command and control unit 16.

In fact, without the pilot light 21, the valves 12 and 14 must stayclosed, to prevent the leakage of unburnt gases.

An external power source could cause the valves 12 and 14 to open evenwithout the pilot light 21, with consequences for the user's safety.

Following the detection that the threshold conditions have beenexceeded, the command and control unit 16 is configured to close thevalves 12 and 14 and block the functioning of the user apparatus.

The sensor 29 is also configured to measure the difference in theelectric voltage between the heads of the two thermoelectric powersources 22 and 23 and, if it is comprised within a predetermined voltagerange, the sensor 29 is configured to send an alarm signal 30.

It is clear that modifications and/or additions of parts may be made tothe valvular control circuit 10 as described heretofore, withoutdeparting from the field and scope of the present invention.

It is also clear that, although the present invention has been describedwith reference to some specific examples, a person of skill in the artshall certainly be able to achieve many other equivalent forms ofvalvular control circuit 10, having the characteristics as set forth inthe claims and hence all coming within the field of protection definedthereby.

In the following claims, the sole purpose of the references in bracketsis to facilitate reading: they must not be considered as restrictivefactors with regard to the field of protection claimed in the specificclaims.

1. Valvular control circuit comprising a first valve element coupledwith a manual drive member to generate a pilot light, a second valveelement coupled with a second valve switch, a control and command unitcoupled with a DC/DC electric voltage converter and able to command saidsecond valve switch via a command signal, a first thermoelectric powersource coupled with said DC/DC electric voltage converter, and a secondthermoelectric power source coupled with at least one of either saidfirst valve element or said second valve element, said thermoelectricpower sources both being fed by said pilot light.
 2. Circuit as in claim1, wherein said first valve element is coupled with a first valve switchand said control and command unit is able to command said first valveswitch by means of a command signal.
 3. Circuit as in claim 1, whereinsaid first thermoelectric power source is coupled with said second valveelement, and said second thermoelectric power source is coupled withsaid first valve element.
 4. Circuit as in claim 1, wherein said secondthermoelectric power source is coupled with said first valve element andwith said second valve element.
 5. Circuit as in claim 1, wherein saidsecond thermoelectric power source comprises a thermocouple.
 6. Circuitas in claim 1, wherein at least one of either the two thermoelectricpower sources comprises a thermopile.
 7. Circuit as in claim 1, furtherincluding a rechargeable energy source removably coupled with said DC/DCelectric voltage converter and with said control and command unit. 8.Circuit as in claim 1, wherein said control and command unit has, or isconnected to, at least a monitoring device able to monitor theelectromotive force generated by one or both of said thermoelectricpower sources and to signal their functioning state and/or wear inrelation to the electromotive forces measured.
 9. Circuit as in claim 1,wherein said control and command unit has, or is connected to, a sensorable to detect the electric voltage of one or both of saidthermoelectric power sources and, if said electric power voltagedetected is greater than a threshold value of electric voltage, or thedifference of electric voltage between said thermoelectric power sourcesis comprised in a predetermined voltage range, said sensor is configuredto send an alarm signal.
 10. Circuit as in claim 1, wherein saidthermoelectric power sources are equal, or they have one or morecharacteristic parameters chosen from a group comprising time constant,electric resistance and electromotive force which can be generated, thatare different from each other.